Some blame it on climate change, others on the "use of juju" and others on Zambians who encroach into the Zimbabwean territory for fishing expeditions. Others claim that whites invented a type of fish that only eats, and has wiped out all the kapenta fish in the Zambezi River.
Well, whatever the reasons might be, the truth that does not need a rocket scientist to come to a conclusion that the catch of kapenta fish by fisherman in Binga per day, week, month and year is definitely dwindling.
Kapenta stocks in the Zambezi River are depreciating at unprecedented volumes amid revelations of overfishing especially by Zambians who have about 830 rigs against 364 run by Zimbabweans. Zimbabwe Parks and Wildlife Management Authority has also proposed an annual three to four months moratorium on kapenta fishing in the river towards a sustainable fishery.
Parks public relations manager Ms Caroline Washaya-Moyo emphasised the need for the industry to be sustainable. She said there has been a wide consultative process with stakeholders and operators in the kapenta industry following a decline in catches. She added that operators have agreed to stop fishing for a certain period, but unanimously called for action to be taken by Zambia in addressing the imbalance that is shortchanging the Zimbabwe kapenta fishery.
"Zimbabwe Parks and Wildlife Management Authority refutes claims that there is or was stoppage of kapenta fishing in Lake Kariba. What transpired is a wide consultative process with stakeholders or operators in the kapenta industry. This was after an outcry from them concerning the declining catches.
"We received feedback on research we carried out on the kapenta stock. We discovered that the reason behind the catch decline could be that of too many fishing units (rigs) for the resource available," she said.
Ms Washaya-Moyo said they just carried out a consultative process and more deliberations should be done with Zambian authorities before taking any action.
"We sought their views to make the process transparent. The operators were in agreement over suspending fishing activities for certain period but unanimously called for action to be taken by Zambia in addressing the imbalance that has been shortchanging the Zimbabwe kapenta fishery.
"Article (6) of the Protocol on Economic and Technical Co-operation between Zimbabwe and the Zambian Government concerning management and development of fisheries on Lake Kariba and transboundary waters of the Zambezi River signed in 1999 states that fishing efforts were to be shared according to the percentage of the lake each country holds (meaning Zimbabwe was entitled to 55 percent and Zambia 45 percent). Currently, the ratio is 70:30 in favour of Zambia which has approximately 830 rigs and Zimbabwe has approximately 364 rigs," said Ms Washaya-Moyo.
After all, at a time when tourism is still in the woods for this district, fishing has become the backbone of Binga and therefore the reduction in fish in the river becomes a cause for concern for the communities.
Interviews with fishermen in Binga recently revealed a reduction in their kapenta catch. Those who used to catch four tonnes per month said they were netting only two tonnes while those who used to catch 10 000 tonnes had gown down to about 6 000 tonnes.
Kapenta is eaten by most Zimbabweans and is served as a snack and starters in hotels. Over the years, the dip net method has proved to be most productive, together with high-technology fish finders, hydraulic winches, etc.
Dip nets are suspended from a boom on the rigs. They are fitted onto a 6- or 7-metre diameter ring -conical in shape and some 10 or 12 metres long. To commence fishing during darkness (kapenta are attracted by light) the nets and underwater lights are lowered into the water and the overhead lights switched on to attract kapenta into the vicinity of the rig.
After half an hour or so, the overhead lights are switched off to concentrate the shoal around the underwater light just above the net. The net is lifted at least three or four times during the night - more when the season is good. The kapenta thus caught are transferred into baskets and coarse salt added to maintain freshness.
Upon returning to harbour in the morning, the fish is placed onto drying racks where it is sun dried losing two thirds of its wet weight. This dried high protein product has the benefit of having a long "shelf life" and easily transported into remote areas without refrigeration.
So over the years, the catch according to the fisherman, has been good until recently. The million-dollar question is: What is causing the fall in kapenta fish catches?
Scientists did research on the effects of climate change on fishing on Lake Kariba and there seems to be similar observation as that taking place on the upper side of the lake in Binga.
According to a study entitled "The Implications of a Changing Climate on the Kapenta Fish Stocks of Lake Kariba, Zimbabwe" by Mzime Regina Ndebele-Murisa, Emmanuel Mashonjowa and Trevor Hill, rainfall is decreasing at a rate of 0,63mm per year around Lake Kariba, while evaporation rates have increased by 31 percent at an average rate of 2,77mm per year since 1963.
"The temperatures around the Kariba area have been rising since 1964; with the maximum range increasing at a faster rate than the minimum temperatures. Kapenta fish production has decreased significantly since 1974 at an average rate of 24,19 metric tonnes per year.
"This pattern of decrease was also observed in the artisanal fish catches that have declined at an average rate of 37,26 metric tonnes per year between 1974 and 2003. All the climatic factors as well as the water levels could explain variations in the kapenta fish catches with the water levels exerting the greatest influence (R 2 = 0,84, P 0,05); followed by maximum temperature (R 2 = 0,72, P = 0,05), evaporation and rainfall.
"In turn, water levels are largely influenced by climate with temperature and rainfall explaining a significant portion of the variation in the water levels (R 2 = 0,99, and R 2 =0,93, P = 0,05) in that order. This suggests that both climate (maximum temperature in particular) and nutrients, which are influenced by water levels, are the primary determinants of Lake Kariba's kapenta production.
"Concerning are the possibilities that a changing climate in and around the lake may continue to adversely affect water levels, the stratification cycle, nutrient fluxes and the kapenta fish production in the lake," reads part of the research.
In summary, therefore, increased water temperature influences the thermal stratification and internal hydrodynamics of lakes. In warmer years, surface water temperatures are higher, evaporative water loss increases, summer stratification occurs earlier in the season, and thermo clines become shallower (IPCC, 2007), thereby adversely affecting nutrient levels and availability and consequently the production chain in the lakes.
According to a local fisherman, there has been an influx of fishing rigs from both sides of the lake.
Mr Obert John Katakula, a fisherman who has been in the business since 1993, said the lake has been besieged by rigs and the kapenta fish are no longer attracted by the underwater lights. He said even if it is at night, the kapenta think it is still day because of the flooding of rigs.
"Day and night, it is now the same to these kapenta. What needs to be done by Zimbabwe National Parks and Wildlife Management Authority is further regulation of the fishing industry. This can came through limiting rigs on the river and stiffer penalty for rigs that fish in breeding places. As things stand now, catches are dwindling as a result of flooding of fishing rigs," he said.
Mr Katakula said the only solution was the use of kapenta fish finders which he said are used to tell where the kapenta will be located.
"These are expensive, but we have no choice. But still the problem remains, we are too many and we all end up having the finders, we will run the lake dry of kapenta," he said.
However, some fisherman believe that their counterparts use "juju" to attract fish to their rigs.
"How can you explain a situation where you are just a few metres apart but you see your fellow fisherman catching more kapenta and you go home empty-handed? Some use 'juju' and it is not fair," said another fisherman.
Some who unfortunately can't prove their theory have said "the white man" has created some fish that only eats on kapenta and that is causing the fall in kapenta margins.
There are more than 15 active fishing co-operatives in the area and each co-operative is only allowed to send in three rigs per night. The co-operatives are calling for the authorities to allow them to have at least four or five rigs so that they increase the catch per night.
"We are in consultation with Parks so that they increase our permits because each rig is supposed to have a single permit."
Since fishing can be a lucrative business for the ordinary people, the authorities ought to help them by controlling fishing of both Zambians and Zimbabweans since restricting the latter might be useless when the other part is not taking heed. Whatever other reasons the fisherman might give on the dwindling of their kapenta catch, the fact remains that climate change is likely to be exerting much influence on biotic interactions in aquatic ecosystems.
Climate change has reduced phytoplankton productivity and fish production.